CN102006898A - Method and devices for monitoring flow circuits - Google Patents

Abstract

A device is provided for monitoring the integrity of a flow circuit in fluid communication with a receptacle. The flow circuit comprises a pumping device for transferring fluid through the flow circuit. The device operates according to a monitoring method in which a pressure signal is received (401) from a pressure sensor, the pressure signal being indicative of fluid pressure in the receptacle or the flow circuit. The pressure signal is then processed (406-407) for detection of a beating signal. The beating signal manifests itself as an amplitude modulation of the pressure signal and is formed by interference between pressure waves generated by a pulse generator associated with the receptacle and pressure waves generated by the pumping device. The integrity of the flow circuit is determined (408-409) based at least partly on the presence or absence of the beating signal. The device and the flow circuit may be part of an apparatus for extracorporeal blood treatment, and the method may be implemented as a computer program product.

Description

Be used to monitor the method and apparatus of flow circuits

Technical field

Present invention relates in general to monitor flow circuits (flow circuit), specifically, relate to the integrity of monitoring flow circuits based on pressure measxurement.The present invention's acquiescence (i.a.) can be applicable to the flow circuits at extracorporeal blood treatment (extracorporal blood treatment) use, comprises the extracorporeal blood flow loop.

Background technology

In extracorporeal blood treatment, patient blood is extracted out, handles, then imported again in this patient body by the extracorporeal blood flow loop.In general, blood installs via this circuit cycle by one or more pumping (bumping).This loop is connected to patient via vascular access (access) (typically adopt the form of one or more access device, as be inserted into needle tubing (needle) or conduit (catheters) in the patient's blood vessel).This extracorporeal blood treatment comprises: hemodialysis (hemodialysis), hemodiafiltration (hemodiafiltration), blood filtration (hemofiltration), plasmapheresis (plasmapheresis) etc.

In extracorporeal blood treatment, extremely important is to minimize the risk of extracorporeal blood flow loop fault, because they may cause the situation of the potential patient's of jeopardizing life.If fluff relative of access device (tremulous pulse needle tubing/conduit) for example with blood vessel because of being used to draw blood, cause air to be inhaled in this loop, perhaps because of the access device that is used to transfuse blood (for example, vein needle tubing/conduit) fluffs, cause patient in a few minutes, to drain blood, vascular access interrupts, and then serious situation may occur.Other fault may cause because of vascular access becomes to block or intercept, and for example, because of the too close blood vessel wall of access device, perhaps is stressed because of the pipeline in the extracorporeal blood flow loop or twists together and cause.

For this reason, the equipment that is used for extracorporeal blood treatment can comprise one or more monitoring arrangement, the integrity in described monitoring arrangement monitor blood flow loop and no matter when detect the potential danger situation and all send alarm and/or make and take appropriate action.This monitoring arrangement can be to operating from the measuring-signal of one or more pressure transducer in this loop.Say that conventionally this monitoring is by relatively one or more measured stress level and one or more threshold value are carried out.For example, the blood drawing fault may relate to air and be imported in this loop, and thus, measured pressure may be near atmospheric pressure, and perhaps blood flow gets clogged or intercepts, and thus, measured pressure may drop to reduced levels.The fault of can't transfusing blood may detect along with reducing of this measured pressure.Yet, may be difficult to be provided with appropriate thresholds, because the pressure in the loop may change with processing, and during handling, change, for example,, patient changes owing to moving.

For increasing monitoring accuracy, WO 97/10013 has proposed, and as one in several options, detects the heart signal in the measured pressure and utilizes the indicator of this heart signal as the integrity in this loop, the particularly indicator of the integrity of vascular access.This heart signal represents to be produced and be sent to via this vascular access device from patient's blood circulation by heart of patient the pressure wave in extracorporeal blood flow loop.Fault in the vascular access will be interrupted the transmission of the pressure wave of heart generation to this loop, disappear even cause heart signal to change.Measured pressure also comprises by the strong pressure wave that blood pump produced in the extracorporeal blood flow loop.In WO 97/10013, this monitoring relates to measured pressure signal filtering is derived from the frequency component of this blood pump with removal, then detects heart signal by analyzing through the filtering pressure signal.Yet, if heart signal is very weak and/or heart beat frequency (beat frequency) near arbitrary frequency component of blood pump, this heart signal may become and can't detect and will produce the warning signal of mistake.This situation due to illness human heart beat frequency (and usually also because frequency of blood pump) changes during handling and can not occur.

Other technical field also may occur to the monitoring flow circuits integrity in requisition for.

Summary of the invention

An object of the present invention is, overcome the limitation of recognizing more than one or more of prior art at least in part.Specifically, a purpose is, provides a kind of and is used to utilize pressure measxurement to monitor the alternative or the additional technology of the integrity of flow circuits, and it is preferably at the definitiveness that has increase aspect the fault that detects flow circuits.

This purpose or other purpose that present according to following description realize that by method, device, computer program and equipment according to independent claims its embodiment is limited by dependent claims at least in part.

The present invention relates to be used to monitor the technology of the integrity of flow circuits, this flow circuits comprises pumping installations and is communicated with container (receptacle) fluid.At its different aspect, an inventive concept of the present invention relates to utilizing in the pressure signal and exists or do not have Beat Signal (beating signal), estimates the integrity of flow circuits.This Beat Signal shows as the Modulation and Amplitude Modulation of pressure signal, and by the pressure wave that pumping installations produced in the flow circuits with by and the pressure wave that pulse generator produced that is associated of this container between interference form.Replace managing in the isolated pressure signal, by the component of signal that pulse generator produced, discern the existence of sort signal component thus via the quadratic effect of beat.In general, beat is a kind of in the especially tangible phenomenon together time of two signal plus with nearest neighbor frequency.Thereby this Beat Signal detects and is more suitable in essence when prior art is failed, that is, use during near the frequency component of pumping installations at patient's heart frequency.

In context of the present disclosure, " not existing " Beat Signal can hint that this Beat Signal disappears, and perhaps is regarded as " existence " with Beat Signal and compares, and fully reduces on value at least.Assessment exists or do not exist can relate to based on pressure signal calculates estimated parameter and relatively this parameter value and threshold value.

Should be understood that the foregoing invention notion can the use in addition in the extracorporeal blood treatment field.Basically, can use it for the monitoring any kind, wherein pumping installations to and/or from the integrity of the flow circuits of container (that is, the being not only patient) transmitting fluid of any kind.The pulse generator of any kind can produce pressure wave in this container, and the pressure transducer of any kind can be used to measure the pressure in this flow circuits.As long as detect pressure wave in can the measured pressure in flow circuits from this pulse generator, perhaps have enough big value in the measured pressure of this pressure wave in flow circuits, just the integrity of this flow circuits can be considered as undamaged.

A first aspect of the present invention is a kind of method that is used to monitor the integrity of the flow circuits that is communicated with fluid container, described flow circuits comprises the pumping installations that is used for by described flow circuits transmitting fluid, said method comprising the steps of: receive the pressure signal from pressure transducer, described pressure signal is represented the fluid pressure in described container or the described flow circuits; Handle described pressure signal, with detect by and the pressure wave that pulse generator was produced that is associated of described container and by the formed Beat Signal of the interference between the pressure wave that described pumping installations was produced; And at least in part based on the existence of described Beat Signal or there is not to determine the integrity of described flow circuits.

In one embodiment, by detecting described Beat Signal at the described pressure signal of time-domain analysis.

In one embodiment, described method is further comprising the steps of: obtain one or more characteristic frequency relevant with the pumping frequency of described pumping installations; At least one has removed the filtering pressure signal of all other characteristic frequency except that in described one or more characteristic frequency with generation.Can handle described filtering pressure signal subsequently, to detect described Beat Signal.Described at least one characteristic frequency can comprise one or more in half of described pumping frequency, described pumping frequency and the harmonics thereof.

In one embodiment, the treating step comprises the step of the envelope of determining described filtering pressure signal.The step of described definite envelope comprises the step of from described filtering pressure signal extraction time order peak value array.Described treatment step also comprise based on described envelope calculate a plurality of derivatives and and variance at least one.

In one embodiment, described method comprises that also at least a portion of comparing described filtering pressure signal and one or more predetermined signal patterns are to detect the step of described Beat Signal.

In one embodiment, described at least one characteristic frequency is obtained by at least one step in the following steps: at the described pressure signal of frequency-domain analysis to discern described one or more characteristic frequency; Derive the frequency measurement signal from described pumping installations; And value of setting that derives the controller of the described pumping frequency be suitable for controlling described pumping installations.

In one embodiment, described method is further comprising the steps of: handle described pressure signal to detect the component of signal that described pulse generator is produced, wherein, also based on the existence of described component of signal or there is not an integrity of determining described flow circuits.

In one embodiment, described processing pressure signal is condition with the step that detects Beat Signal there not to be described component of signal in described pressure signal.

In one embodiment, described method is further comprising the steps of: make when not having Beat Signal predetermined the change taken place in the described pumping frequency of described pumping installations.

In one embodiment, described method is further comprising the steps of: make the temporary transient inertia of described pumping installations; Discern the frequency of described pulse generator; And make described pumping installations by so that all associated frequencies components all activate with respect to this pumping frequency of the frequency shift (FS) of described pulse generator.

In one embodiment, realize described treatment step at the local overlap signal section of a sequence of described pressure signal, the length of each section is specified according to scheduled time window.

A second aspect of the present invention is a kind of method that is used to monitor the integrity in the extracorporeal blood flow loop that is connected to patient's blood vessel, described extracorporeal blood flow loop comprises blood pumping device, said method comprising the steps of: receive the pressure signal from the pressure transducer in the described blood flow loop; Handle described pressure signal, the pressure wave that produces with the heart that detects by described patient with by the formed Beat Signal of interference between the pressure wave of described blood pumping device generation; And at least in part based on the existence of described Beat Signal or there is not to determine the integrity in described blood flow loop.

A third aspect of the present invention is a kind of equipment that is used to monitor the integrity of the flow circuits that is communicated with fluid container, described flow circuits comprises the pumping installations that is used for by described flow circuits transmitting fluid, described equipment comprises: input part, this input part is used to import the pressure signal from pressure transducer, and described pressure signal is represented the fluid pressure in described container or the described flow circuits; And signal processor, this signal processor comprises first module, this first module is configured to handle described pressure signal, with detect by and the pressure wave that pulse generator was produced that is associated of described container and by the formed Beat Signal of the interference between the pressure wave that described pumping installations was produced, described signal processor is configured to, at least in part based on the existence of described Beat Signal or there is not to determine the integrity of described flow circuits.

In one embodiment, described first module is configured to, by detecting described Beat Signal at the described pressure signal of time-domain analysis.

In one embodiment, described first module also is configured to, obtain one or more characteristic frequency relevant with the pumping frequency of described pumping installations, and be configured to, generate at least one filtering pressure signal, in this filtering pressure signal, removed all other characteristic frequency except that in described one or more characteristic frequency.

In one embodiment, described first module also is configured to, and determines the envelope of described filtering pressure signal.

In one embodiment, described first module also is configured to, and determines described envelope by extraction time from described filtering pressure signal order peak value array.

In one embodiment, described first module also is configured to, based on described envelope calculate a plurality of derivatives and and variance at least one.

In one embodiment, described first module also is configured to, and compares at least a portion of described filtering pressure signal and one or more predetermined signal patterns to detect described Beat Signal.

In one embodiment, described signal processor comprises second module, this second module is configured to, handle described pressure signal to detect component of signal by described pulse generator was produced, wherein, described signal processor is configured to, also based on the existence of described component of signal or there is not to determine the integrity of described flow circuits.

In one embodiment, described signal processor is configured to, and operates described first module and described second module in order, so that described first module is only operated when described second module can't detect described component of signal in described pressure signal.

In one embodiment, described signal processor is configured to, and makes the described pumping frequency of described pumping installations that predetermined the change taken place when not having Beat Signal.

In one embodiment, described signal processor is configured to, make the temporary transient inertia of described pumping installations, discern the frequency of described pulse generator, and described pumping installations is all activated with respect to this pumping frequency of the frequency shift (FS) of described pulse generator with all associated frequencies components.

A fourth aspect of the present invention is a kind of equipment that is used to monitor the integrity of the flow circuits that is communicated with fluid container, described flow circuits comprises the pumping installations that is used for by described flow circuits transmitting fluid, described equipment comprises: be used to receive the device from the pressure signal of pressure transducer, described pressure signal is represented the fluid pressure in described container or the described flow circuits; Be used to handle described pressure signal, with detect respectively by and the pressure wave that pulse generator was produced that is associated of described container and by the device of the formed Beat Signal of interference between the pressure wave that described pumping installations was produced; And be used at least in part based on the existence of described Beat Signal or do not have to determine the device of the integrity of described flow circuits.

A fifth aspect of the present invention is a kind of equipment that is used to monitor the integrity in the extracorporeal blood flow loop that is connected to patient's blood vessel, described extracorporeal blood flow loop comprises blood pumping device, said method comprising the steps of: be used for receiving the device from the pressure signal of the pressure transducer in described blood flow loop; Be used to handle described pressure signal, pressure wave that produces with the heart that detects by described patient and device by the formed Beat Signal of interference between the pressure wave of described blood pumping device generation; And be used at least in part based on the existence of described Beat Signal or do not have to determine the device of the integrity in described blood flow loop.

A sixth aspect of the present invention is a kind of computer program, and this computer program comprises and is used to make a computer to carry out according to first or the instruction of the described method of second aspect.

A seventh aspect of the present invention is a kind of equipment that is used for extracorporeal blood treatment, this equipment comprises the extracorporeal blood flow loop, this extracorporeal blood flow loop comprises blood pumping device, be arranged in the described blood flow loop pressure transducer and according to the described equipment in the 3rd, the 4th or the 5th aspect.

According to following detailed, according to appended claims and with reference to the accompanying drawings, more other purposes of the present invention, feature, aspect and advantage will present.

Description of drawings

Below, with reference to accompanying schematic figure, embodiments of the present invention are described in more detail.

Fig. 1 is the sketch map that is used for hemodialysis system that handle, that comprise extracorporeal blood circuit.

Fig. 2 is the sketch map that is connected to the extracorporeal blood circuit of monitoring arrangement.

Fig. 3 (a) is the time domain plot that comprises the vein pressure signal of pumping frequency component and heart signal, and Fig. 3 (b) is the frequency domain plot of respective signal.

Fig. 4 is the flow chart of processing that is used for the integrity in monitoring of blood loop.

Fig. 5 is the block diagram of data-analyzing machine that is used for the processing of execution graph 4.

Fig. 6 (a) and 6 (b) are illustrated in by the direct detection module in the data-analyzing machine of Fig. 4 to handle before and the plot of the power spectrum of pressure signal afterwards.

Fig. 7 is that the direct detection module of illustration is at the different figure of the performance of value relatively between blood pulse and the cardiac pulses.

Fig. 8 (a) and 8 (b) are having and are not having under the situation of heart signal, the time domain plot of the pressure signal after handling in the beat detection module in the data-analyzing machine of Fig. 5.

Fig. 9 (a) and 9 (b) are the enlarged drawings of the plot of Fig. 8 (a) and 8 (b).

Figure 10 (a) and 10 (b) are the plots according to the envelope of the data fetch of Fig. 9 (a) and 9 (b).

Figure 11 is having and is not having under the situation of heart signal, calculate according to envelope, as a plurality of derivatives of time function and plot.

Figure 12 is having and is not having under the situation of heart signal, calculate according to envelope, as the plot of the variance of time function.

Figure 13 is an illustration beat detection module at the figure of the performance of the different relative values between blood pulse and the cardiac pulses.

Figure 14 is the direct detection of illustration combination and beat detection module at the figure of the performance of the different relative values between blood pulse and the cardiac pulses.

Figure 15 is the sketch map of structure (arrangement) of analog that is used for the beat component of detected pressures signal.

Figure 16 (a) and 16 (b) are the sketch maps that can utilize the flow circuits structure that embodiment of the present invention monitors.

The specific embodiment

Hereinafter, under the background of extracorporeal blood treatment, embodiments of the present invention are described.Yet the inventive concept on disclosed embodiment and basis can be used outside this background, as illustrated in will be in the ending of this description.

Run through following description, same parts is indicated with corresponding label.

Fig. 1 shows the extracorporeal blood circuit type of using in dialysis machine (dialysis machine).As shown in Figure 1, this loop comprises tremulous pulse needle tubing 1 and tremulous pulse needle tubing 1 is connected to the tremulous pulse pipeline section 2 of blood pump 3 that this blood pump 3 can be the wriggling type.In the porch of this blood pump, have pressure transducer 4a (hereinafter, being called the tremulous pulse pick off), its measure in tremulous pulse pipeline section 2, the pressure before this blood pump.Blood pump 3 promotes blood via pipeline section 5 to dialyser 6.Many dialysis machines all are provided with pressure transducer 4b in addition, and this pressure transducer 4b measures the pressure between blood pump 3 and the dialyser 6, so-called system pressure.Blood leads to intravenous drip device (venous drip chamber) or degasser (deaeration chamber) 11 from dialysis machine 6 via pipeline section 10, and is back to patient via vein pipeline section 12 and vein needle tubing 14 therefrom.Degasser 11 is provided with pressure transducer 4c (hereinafter, being called intravenous sensor), and this pressure transducer 4c measures the pressure in this intravenous drip device.Tremulous pulse needle tubing 1 and vein needle tubing 14 all are connected to patient by vascular access.This vascular access can be any suitable type, for example, and fistula (fistula), Scribner diverter, one or more conduit, graft (graft) etc.At the purpose of discussing below, suppose that vascular access is a fistula.

When blood during by tremulous pulse needle tubing 1 (its have small cross sections long-pending so that do not damage fistula), pressure with respect to ambient atmosphere be reduced to approximately-200mm Hg is between-50mm the Hg, this is by tremulous pulse pick off 4a measurement.This pressure rises in blood pump 3, and described pressure is measured by system sensor 4b.In dialyser 6, pressure reduces because of flow resistance wherein, and utilizes intravenous sensor 4c to measure this dialyser pressure afterwards, and this intravenous sensor is connected usually with the pressure in the measure venous instillator 11.Pressure in the intravenous drip device 11 usually at+50mm Hg between+the 150mmHg.Finally, blood is released into fistula via vein needle tubing 14, thus, in this needle tubing pressure drop takes place because of the small cross sections that flows through this vein needle tubing is long-pending.

The aforementioned pressure situation significantly changes with patient, even can become at same patient between the different course (treatmentsession) and during the same course of treatment.Therefore, be difficult to set up threshold value, so that represent different mistake/malfunctions at pressure transducer.In many dialysis machines, one or more among the described pressure detector 4a-4c do not exist.Yet, have at least one venous pressure sensor.As discussing by foreword, it is essential, the integrity in monitoring of blood loop, specifically, at the integrity of monitoring this vascular access in the fault of blood being injected and/or extract vascular access out.

Fig. 1 also shows and is engaged to patient separably to measure the optional pulsimeter 30 of heart pulse rate rate.This pulsimeter 30 can be any in pulse watch, pulse oximeter, electrocardiograph (electrocardiograph), ultrasoundcardiogram (echocardiogram), microphone (microphone), the pulse band (pulse belt), any form in plethysmography (plethysmography), photoplethy smography (photoplethysmography), blood pressure cuff (blood pressure cuff) or its any combination.

Fig. 2 is another schematic illustration figure of extracorporeal blood circuit 20, comprises blood pump 3 and pressure transducer 4 (among the pick off 4a-4c in the presentation graphs 1 one).Default setting control unit 23, come blood flow in the control loop 20 with rotating speed by control blood pump 3.Blood circuit 20 and control unit 23 can be formed for the part of the equipment 24 (as dialysis machine) of extracorporeal blood treatment.Although not shown or further discussion should be understood that this equipment 24 carries out many other functions, for example, the temperature of the flowing of control dialysis fluid, control dialysis fluid with become to grade.

Supervision/monitoring device 25 is connected to equipment 24, and is configured to the integrity in monitoring of blood loop 20, specifically, exists the component of signal that is derived from heart of patient to monitor this integrity in blood pressure signal by monitoring.Do not exist the sort signal component to be regarded as indication, and make device 25 active alarms and/or stop blood flow by stopping blood pump 3 to the integrity failure of blood circuit 20.Monitoring arrangement 25 is connected to equipment 24 at least to receive the signal of the measuring-signal of representing pressure transducer 4.As shown in Figure 2, device 25 can also be connected to control unit 23.Alternative or additionally be, device 25 can be connected to measuring device 26, and this measuring device 26 is used to indicate the frequency of blood pump 3.This device 25 is connected to Local or Remote device 27 in wired or wireless mode, and this Local or Remote device 27 is used for producing can be listened/visual/tactile alert or alarm signal.Monitoring arrangement 25 and/or alarm device 27 can be alternatively as the part of equipment 24 and install.

In Fig. 2, monitoring arrangement 25 comprises the data acquiring section 28 that is used to anticipate input signal, this data acquiring section 28 for example comprises A/D converter, one or more signal amplifier, one or more wave filter with required minimum sample rate and resolution, what this wave filter was used for removing this input signal does not wish component, disturbs as skew, high-frequency noise and supply voltage.

Be in this example that provides, data acquiring section 28 comprise from DAQ card USB-6210 National Instrument, that have 1kHz sample rate and 16 bit resolutions, from the operational amplification circuit AD620 of AnalogDevices, have 0.03Hz cut-off frequency high pass filter (acquiescently, be used to remove signal bias) and low pass filter (acquiescently, being used to remove high-frequency noise) with cut-off frequency of 402Hz.In order to obtain low convergence time, higher order filter (3-4 rank) is used for high pass filter.And data acquiring section 28 can comprise the additional fastening band filter of the upper and lower cut-off frequency that has 0.5Hz and 2.7Hz (corresponding to the heart pulse rate rate between per minute 30 bats and per minute 160 bats) respectively.This wave filter can be used to suppress the outer interference of the frequency separation of paying close attention to.

After the anticipating in data acquiring section 28, will offer data analysis portion 29 as input from the signal of pressure transducer 4, this data analysis portion 29 carries out actual monitoring and handles.Fig. 3 (a) shows this through the example of pretreated pressure signal in time domain, and Fig. 3 (b) shows corresponding power spectrum, that is, and and the pressure signal in the frequency domain.This power spectrum has represented, and the pressure signal that is detected comprises a plurality of different frequency components that send from blood pump 3.In illustrated example, at the fundamental frequency (f of blood pump ₀) (in this example, being 1.5Hz) locate to exist frequency component, and have its harmonics 2f ₀, 3f ₀And 4f ₀This fundamental frequency (also referring to the pumping frequency below) is the frequency that produces the pump stroke of pressure wave in blood circuit.For example, in peristaltic pump type shown in Figure 1, at each living two pump stroke of changing the line of production entirely of rotor.Fig. 3 (b) also indicates and has half pumping frequency (0.5f ₀) frequency component and the harmonics thereof located, in this example, there is f at least ₀, 1.5f ₀, 2f ₀And 2.5f ₀Fig. 3 (b) also shows heart signal (1.1Hz), and it is approximately than fundamental frequency f in this example ₀Weak 40 times of the blood pump signal at place.

The embodiment that will describe has been designed to specifying minimal reaction to detect the fault of blood circuit 20 in the time below.Analyze each section pressure signal to detect this fault by data analysis portion 29.Signal segment is long more, and monitoring accuracy is high more, but response time is also long more.On the contrary, signal segment is short more, and response time is also short more, reduces but cost is a monitoring accuracy.As a kind of compromise proposal, preferably in overlapping regular length time window, analyze pressure signal, that is, analyze the overlap signal section.For example, this time window can be in importing pressure signal into by second displacement so that signal segment overlaps in succession, but be not at one second data.Be in this example that provides, the time window in 20 seconds is used to limit the signal segment that will analyze.

In a modified example, can handle/analyze the signal segment of different length, detect the fault of blood circuit.The sort signal section may overlap or not overlap.In a this embodiment, the length of signal segment (time window) can be set to adaptively the function of rate of blood flow, for example, the function that obtains according to the rotating speed or the pumping frequency of blood pump.For example, because the influence of incipient fault is more serious under low rate of blood flow, so the length of signal segment can increase along with reducing of rate of blood flow.In another embodiment, can walk abreast or the signal segment of sequential processing/analysis different length, detect the fault of blood circuit.For example, and when the combination of using each detection method comes detection failure (for example, as shown in Figure 4, referring to following), different detection methods can work to the signal segment of different length.And, if same method uses the combination of estimated parameter to come detection failure (for example, shown in Figure 11 and 12, referring to following), then can derive different evaluate parameters by the signal segment of processing/analysis different length.

Fig. 4 is data analysis according to an embodiment of the present invention or monitors the flow chart of handling.Shown in the combination of processing execution detection method, take the integrity in monitoring of blood loop.A kind of detection method (" directly detect ") relates to frequency component in the detected pressures signal, that send from heart of patient.Another detection method (" beat detection ") relates to the Modulation and Amplitude Modulation (Beat Signal) in the detected pressures signal, and this Modulation and Amplitude Modulation is caused by the interference between the pressure wave that is derived from heart of patient and blood pump.Below, these detection methods are described in more detail, but at first, summarize the overall operation of this processing.

This monitoring handle the signal segment (step 401) that starts from input pressure signal and with the fundamental frequency (f of blood pump ₀) relevant information (step 402).This frequency information can be derived from the processing of pressure signal itself.Alternatively, this frequency information can be derived (with reference to 26 Fig. 2) from the signal that special measurement device produced, and perhaps derives (with reference to 23 Fig. 2) from expression by the signal of employed value of setting of control unit or actual value.Should be understood that not and need take turns monitoring and handle all execution in step 402 at every.

Direct detecting method relates to step 403-405, and wherein, the processing signals section is to stop one or more frequency component relevant with blood pump (referring to the 0.5f among Fig. 3 ₀, f ₀, 1.5f ₀, 2f ₀, 2.5f ₀, 3f ₀And 4f ₀).Say that typically step 403 is designed to remove effectively all frequency components of sending from blood pump in this signal segment.In step 404, at this signal segment of frequency-domain analysis, to discern any residual frequency component that sends from heart of patient.If detect this heart component in step 405, then this monitoring is back to step 401, in step 401, imports new pressure signal section for processing.As mentioned above, this new signal segment can partly overlap with previous signal segment.If do not detect the heart component in step 405, then this monitoring advances to the beat detection.Lack the heart component may because of the fault of blood circuit or the heart component is too weak and/or on frequency too near due to arbitrary frequency component of blood pump.

The beat detection method relates to step 406-408, wherein, and the Beat Signal that the processing signals section causes because of the interference between the pressure wave that is derived from heart and blood pump respectively with identification.This Beat Signal perceived as frequency and equals cyclically-varying difference on the frequency, signal amplitude between these two pressure waves.Thereby, replacing search cardiac pulses itself in pressure signal, beat detects checks the influence of heart signal to pressure signal on time domain.

In step 406, the processing channel section is to remove other all frequencies except one or more selected frequency band.Each this selected frequency band is to surround the frequency component relevant with blood pump (referring to the 0.5f among Fig. 3 ₀, f ₀, 1.5f ₀, 2f ₀, 2.5f ₀, 3f ₀And 4f ₀) in only one frequency band.Can realize this selectivity bandpass filtering so that detect Beat Signal.From the pressure wave of the heart pressure wave of autoblood pump little (typically little 20-200 doubly) recently usually, thereby potential beat ripple is more weak and may be difficult to detect.Usually, remove all frequencies outside this selected frequency band from signal segment, therefore, in time-domain analysis gained filtering signal section, to detect Beat Signal (step 407).If known blood pump produces a plurality of frequency components (as shown in Figure 3), then step 406 obtains one group of filtering signal section, and each filtering signal section all only comprises the frequency component frequency on every side in these frequency components.These filtering signal sections can walk abreast and produce and then analyze in step 407.Alternatively, the filtering signal section can produce in order based on the designated order of blood pump frequency component.Each filtering signal section can to analyze before producing another filtering signal section, make once detecting the generation that Beat Signal interrupts the filtering signal section to step 407 transmission.

In another embodiment, known heart pulse rate rate.In this case, can conditioning step 406 only producing a filtering signal section, this filtering signal section only comprises the frequency around the frequency component of the most close this known heart frequency.This heart pulse rate rate can obtain by the pulsimeter of incorporating blood circuit into or being attached to patient separably of Fig. 1.Alternatively, this heart pulse rate rate formerly derives in step or the parallel step, wherein, at time domain or frequency-domain analysis pressure signal, with the identification heart frequency, that is, and the heart pulse rate rate.

For example, heart frequency can be derived by step 406 in the previous round monitoring is handled.Optionally, this pressure signal can obtain when cutting off blood pump, so that remove any interference frequencies component that sends from blood pump.Another alternative example is to derive the heart pulse rate rate by analyzing from the pressure signal of another pressure transducer in the blood circuit.For example, if the beat detection method based on pressure signal from intravenous sensor (4c among Fig. 1), then the heart pulse rate rate can be always derives from the pressure signal of tremulous pulse pick off (4a among Fig. 1).In many blood circuits, stronger from the pressure of heart than venous side in arterial side, and may be more weak from the pressure wave of blood pump, this is convenient to determine the heart pulse rate rate based on the pressure signal from the tremulous pulse pick off.

The selectivity bandpass filtering of step 406 can use the fixed width (its hope performance according to this beat detection method is provided with) of this frequency band, is typically the heart pulse rate and the interval of the peak frequency between the pump frequency component that should cause Beat Signal.For example, if the beat detection method and can detect exist/do not have heart signal in the assigned frequency zone between these frequency components another detection method (for example, direct detecting method) be used in combination, the employed frequency band of then beat detection method can be less than the interval of pump frequency component.In other cases, this frequency band can have the approximately overall width identical with the interval of pump frequency component, the frequency band of perhaps adjacent pump frequency component even can overlap.In another embodiment, the width of frequency band can be set to adaptively the function of the previous heart frequency of determining.For example, this width can reduce near one in the pump frequency component along with heart frequency.As mentioned above, heart frequency for example can or be derived the previous round monitoring is handled from independent pulsation rate meter, another pressure transducer.

If detect Beat Signal in step 408, then monitoring is back to step 401, in step 401, imports new pressure signal section for processing.If do not detect Beat Signal in step 408, then monitoring moves on to activate the alarm of indication blood circuit fault, perhaps alarms this fault at least (step 409) may take place.Take place simultaneously with active alarm/warning, processing can advance to step 410, in step 410, changes the pumping frequency, and therefore, monitoring is handled can be back to step 401, to continue the integrity in monitoring of blood loop.If during monitoring is subsequently handled, find heart component/Beat Signal, then can close alerts/alarm.Alternatively, so that minimize false alarm number of times, Cai have only before the monitoring processing can't this variation in the pumping frequency and active alarm/alarm when detecting heart signal afterwards.

In an embodiment of step 410, pump keeps running, but its pumping frequency shift.In a modified example, the pumping frequency is reduced so that reduce blood flow, and minimize any blood loss that causes because of detected incipient fault thus.In another modified example, the pumping frequency initiatively is offset, so that its frequency component is not consistent with its previous frequency component.For example, can be offset fundamental frequency by the sub-fraction at the interval between the frequency component that is derived from pump.In the example of Fig. 3, this means 0.5f ₀Sub-fraction.Say that typically reducing of pumping frequency represented in this skew.

In another embodiment of step 410, pump is shut down (that is f, ₀=0), also minimizes any blood loss that causes because of detected incipient fault simultaneously to remove interference from blood pump.In a modified example of this embodiment, step 410 also relates to discerns heart frequency when blood pump is shut down, then utilize the pumping frequency that is offset according to the heart frequency of discerning like this to restart this blood pump.Heart frequency can for example utilize the spectrum signal analysis of step 404 and discern according to pressure signal.

In another embodiment of step 410, as mentioned above, for example from the independent source 30 known heart pulse rate rates of Fig. 1.The heart pulse rate rate can provide by being contained in pulsimeter 30 in the blood circuit or that be attached to patient separably.In the modified example of this embodiment, step 410 also relates to the pumping frequency with respect to the heart frequency skew blood pump that identifies.Thereby, activating pumping installations with this pumping frequency and activate, this pumping frequency makes the frequency shift (FS) of all associated frequencies components with respect to pulse generator.Pulsimeter 30 can be any in pulse watch, pulse oximeter, electrocardiograph, ultrasoundcardiogram, microphone, the pulse band, any form in plethysmography, photoplethy smography, blood pressure cuff or its any combination.

Fig. 5 is the block diagram of data analysis portion (with reference to 29 among Fig. 2), and it is configured to carry out monitoring shown in Figure 4 and handles.In illustrated embodiment, this data analysis portion comprises: memory module 50, pump frequency determination module 51, direct detection module 52, beat detection module 53 and the handover module 54,55 that is used for the output of direct detection module 52 and beat detection module 53 is connected to alarm device.Although not shown, can provide a control module to carry out synchronously with operation to module 50-55.

Data analysis portion 29 can realize by the software that operates on the blood processor (as universal or special computer installation or programming microprocessor).Memory module 50 can be the volatibility or the nonvolatile memory of this computer installation, and other module 51-55 can realize by software instruction.Yet what can expect is that some or all of modules can realize by the assembly of specialized hardware known in the field (as FPGA, ASIC or discrete electronic components (resistor, capacitor, operational amplifier, transistor etc.)) whole or in part.

Memory module 50 can be operated with storage and be imported pressure signal into, as the data sample sequence.Then other module 51-53 operates to receive or to obtain to have stored the pressure signal section from memory module 50.Memory module 50 cushions thus imports pressure signal into, allows individual processing and analyze to overlap or the disjoint signals section.Memory module 50 for example may be implemented as a plurality of linear buffers or circular buffer.

Module 51 is configured to determine based on signal segment the frequency of blood pump.Below, the example of algorithm that this module is used is described further.

Module 52 is carried out direct detection step 403-405 (Fig. 4) based on the estimation pumping frequency that pump frequency determination module 51 is provided.If the result of determining step 405 is a "No", that is, do not find the heart component, then operate handover module 54 with active module 53.If find the heart component, then can operate handover module 54 and provide the indication of "Yes" state, and module 51,52 can receive or obtain new signal segment to apply to install to announcement to put.

Module 53 is carried out beat based on estimation pumping frequency once more and is detected step 406-408 (Fig. 4).If the result of determining step 408 is a "No", that is, do not detect Beat Signal, then operate handover module 55 so that the indication of "No" state to be provided to alarm device, this alarm device sends alarm.If the discovery Beat Signal then can operate handover module 55 and indicate so that the "Yes" state to be provided to alarm device, and module 51,52 can receive or obtain new signal segment.

In Fig. 5, data analysis portion also comprises the input part 56 of the signal that is used for (for example, measuring device from Fig. 2 26 or control unit 23) reception indication pumping frequency.As discussing at step 410 (Fig. 4), the frequency information of deriving according to this signal can replenish or replace the frequency that module 51 is determined.

Fig. 5 has also indicated and has been provided with input part 57, and this input part 57 is used to import for example will be by the measuring-signal of module heart frequency 53 uses, the indication patient when execution in step 406 and/or step 410.

Below, from pump frequency determination module 51, be described at each the exemplary operations among the module 51-53.

Pump frequency determination module 51 is configured to, and according to pressure signal section rated output spectrum, and discerns pumping fundamental frequency in this power spectrum.Can for example, calculate this power spectrum by any known way by the pressure signal section is carried out DFT (discrete Fourier transform (DFT)) or FFT (fast Fourier transform).The pumping fundamental frequency can be identified as the peak-peak in this power spectrum or the frequency of one of them peak-peak.

If the resolution of power spectrum is lower, then can adopt special measure to increase the precision of estimated frequency.This resolution depends on the sample frequency f in the signal segment _sWith hits N, as f _s/ N.In one example, by the frequency of 10Hz, come signal segment sampling to 20 seconds with the resolution of 0.05Hz.This precision may in the direct detection module 52 and/or the processing in the beat detection module 53 not enough.In order to increase precision, can be around the estimated frequency of deriving from power spectrum come this signal segment is carried out bandpass filtering than close limit, thereby obtain relative noiseless and as the signal segment of sine wave.Then, can be by determine the cycle of filtering signal section in time domain, for example, by with sinusoidal wave self adaptation to the time difference between filtering signal and the identification zero crossing, obtain the fundamental frequency accurately estimated.

Directly detection module 52 can be configured to, and at pressure signal section operation comb filter and/or the combination of (typically cascade couples) band elimination filter, is derived from all frequency components of blood pump with filtering (block out).Alternatively, this filtering can realize by using one or more sef-adapting filter (for instance, as disclosed in aforementioned WO 97/10013).Then, directly detection module 52 for example utilizes DFT or FFT to come the power spectrum of calculation of filtered signal segment, discerns the peak-peak in this power spectrum, and whether assess this peak value enough remarkable.For example, can be at peak value (f _k) square and the meansigma methods of (remove should off peak) a plurality of squared power spectrum values between form one and concern that this relation is provided by following formula:

$\frac{{\mathrm{<figure-callout\; id="2"\; label="f\; k"\; filenames="HPA00001242781900011.png,HPA00001242781900021.png"\; state="\{\{state\}\}">f</figure-callout>}}_k^{}}{\frac{1}{N-1}\underset{i=0}{\overset{N-2}{\mathrm{\&Sigma;}}}{\mathrm{<figure-callout\; id="2"\; label="f\; i"\; filenames="HPA00001242781900011.png,HPA00001242781900021.png"\; state="\{\{state\}\}">f</figure-callout>}}_i^{}}.$

If this relation exceeds predetermined reference level, then determine to exist cardiac pulses.Otherwise do not exist.In this system, this reference level can change (for example, represented by the fundamental frequency of blood pump) with different flow rates.Thereby directly detection module 52 can be visited the data base that reference level is associated with fundamental frequency, to judge.

Fig. 6 (a) shows the power spectrum of the pressure signal section of obtaining at the cardiac pulses of the blood pumping frequency of 1.13Hz and 1Hz, and this cardiac pulses is 1: 60 with relative value between the pumping pulse.Fig. 6 (b) show same signal segment, by the power spectrum after the direct detection module filtering.In this case, the frequency component of blood pump is removed, and has been left cardiac pulses and some noises.

Fig. 7 can utilize aforementioned direct detection module 52 to detect the frequency of cardiac pulses and the example of amplitude range.The frequency range of vertical dotted line indication normal heart, and the indication of horizontal frequency band can detect the frequency of cardiac pulses in the system of the pumping frequency of utilizing 1.13Hz.The horizontal frequency band of the five elements is represented the different relative value between blood pump and the cardiac pulses, walks to top line the end of from, and scope changed to 100: 1 from 20: 1,40: 1,60: 1,80: 1.Be clear that, around the frequency component of blood pump, have wherein the big zone that in direct detection module, can't detect heart signal, and these zones reduce along with the relative value of cardiac pulses and widen.

Beat detection module 53 is configured to, and to signal segment filtering, each passband all comprises a frequency component of blood pump at one group of passband.Each gained filtering signal section is sinusoidal wave basically.If the frequency of heart is arranged within the passband of these passbands, then corresponding filtering signal section will have the waveform that can not find in other filtering signal section any.

Fig. 8 (a) shows the secondary signal section of the narrow passband with the blood pump fundamental frequency that surrounds 1.5029Hz that has carried out filtering.This filtering signal also comprises cardiac pulses, and it has the frequency with respect to fundamental frequency skew 0.037Hz.Blood pump is 40: 1 with relative value between the cardiac pulses.Fig. 8 (b) shows the corresponding filtering signal section that does not have heart signal.Although very little, its difference between can the discernible signal section, wherein, the existence of heart causes the overlapping variation in the signal amplitude among Fig. 8 (a), and does not have in Fig. 8 (b).Fig. 9 (a) and 9 (b) are respectively the enlarged drawings of the signal peak among Fig. 8 (a) and 8 (b), show the notable difference between the filtering signal section that has and do not have cardiac pulses.

In one embodiment, beat detection module 53 is configured to, and detects Beat Signal based on the envelope of deriving according to the filtering signal section.

In a this modified example, beat detection module 53 comes the derived unit envelope line by extracting the peak value array from this signal segment.The peak value of this extraction can obtain by the signal value that is extracted in the independent peak value of being discerned in this signal segment.In order to improve noise robustness, the peak value of each extraction can instead be calculated as the signal value that forms each peak value in this signal segment meansigma methods or and, for example, comprise the signal value in the 10%-25% of peak value, perhaps around the signal value in the fixed time scope of peak value.Then handle the envelope (peak value array) of being derived, to calculate estimated parameter.Figure 10 (a) and 10 (b) show respectively from the peak value array of Fig. 9 (a) and Fig. 9 (b) extraction.

In another modified example, module 53 derives this envelope by using the linear-time invariant filter that is known as the Hilbert changer to signal segment s.This computing obtains the figure signal section

It is 90 ° of phase shifted version of this signal segment.Then, can be according to following formula derived unit envelope line b (n):

Wherein, n is the diverse location in this signal segment.

For improving treatment effeciency, module 53 can derive approximate envelope according to signal segment s based on this relation

$\hat{b}\left(n\right)=\left|s\left(n\right)\right|+\frac{2}{\mathrm{\&pi;}}|s(n+1)-s(n-1)|$

Then, handle approximate or non-proximate, the envelope of being derived, to calculate estimated parameter.

In arbitrary modified example, can be to the envelope low-pass filtering that is derived, before handling, further to remove the envelope noise, to calculate estimated parameter.

In arbitrary modified example, can be with the value of gained estimated parameter and a threshold ratio, to determine to exist or do not exist Beat Signal.

In one example, this estimated parameter be this envelope value derivative absolute and, draw by following formula:

$\underset{n=0}{\overset{N-1}{\mathrm{\&Sigma;}}}\left|(b(n+1)-b\left(n\right))\right|$

Wherein, b (n) is the envelope value at n place, position, and N is the quantity of the value in this envelope.

Figure 11 illustration on 5 minutes pressure signals, move 20 windows in second (one time one second) and calculate at the derivative on the envelope that each 20 second, signal segment was derived definitely and the result.Calculate upper curve at the filtering signal section that comprises heart signal, and calculate lower curve at the filtering signal section that does not have heart signal.Be apparent that, can limit threshold value, have and do not exist heart signal to distinguish.

Upper curve has been showed because of this signal segment and has been comprised the waveform that the part in full Beat Signal cycle causes.Thereby along with the past of time, this signal segment will comprise the different piece of Beat Signal.Because gradient is less and bigger betwixt near the peak value of envelope and peak valley, so the derivative that calculates and will changing accordingly along with the time.Will be appreciated that for the designated length (time window) of signal segment, the detectability of gradient will reduce along with the difference on the frequency between heart and the blood pump and reduce, because this has reduced beat frequency and has made the envelope planarization.Wideer time window will improve detectability, till the amplitude of beat becomes point less than noise.

In another example, estimated parameter is the variance of the value of envelope.Figure 12 corresponding to Figure 11, have (on) and do not have the plot of (descending) heart signal, but illustration as the variance of the function of time.Be apparent that, can limit a threshold value, have and do not exist heart signal with differentiation.

In another example, can reduce the envelope effect of noise, estimated parameter be the average of derivative and, for example draw by following formula:

$\underset{n=1}{\overset{N-1}{\mathrm{\&Sigma;}}}\left|\frac{(b(n+1)-b(n-1))}{2}\right|$

In another embodiment, beat detection module 53 determines to exist or do not exist Beat Signal based on pattern recognition process.For example, all or part of of this signal segment and one or more predetermined signal patterns of expression Beat Signal can be compared.In one example, the envelope of being derived (low-pass filtering alternatively) can with each cross correlation in one group of sine wave of different frequency or convolution otherwise.The correlation curve that each cross correlation/convolution acquisition can be derived maximum related value.Then can be with one a group of maximum related value of gained and a threshold, with determine to exist/do not have Beat Signal, wherein, sufficiently high maximum related value can be considered as indication to this existence.

Determine to exist all above-mentioned examples of Beat Signal can relate to assessment another step of reliability of definite Beat Signal.This assessment can relate to the difference frequency of determining Beat Signal, and checks whether this difference frequency is reasonable.According to how to discern Beat Signal, can perhaps determine difference frequency by handling the envelope of being derived at time domain/frequency domain by the sinusoidal wave frequency of identification generation maximum related value.This difference frequency can be checked by the absolute value inspection and/or at determined one or more difference frequency in previous round monitoring processing (Fig. 4), wherein, can with at the enough big deviation of previous difference frequency/a plurality of frequencies as to the insecure indication of the definite Beat Signal of institute.This assessment can obtain to indicate the reliability scoring of reliability of definite Beat Signal.Alternative or additionally be that reliability assessment can comprise that this pump of control is to change its pumping frequency and to check whether produce the corresponding step that changes in this Beat Signal.For example, the pumping frequency can be offset a little, and perhaps pump can intermittently be shut down.The result of reliability assessment can influence the execution of step 409-410, and for example, whether whether active alarm/warning needed further to repeat monitoring and handle before active alarm/warning, whether will change pumping frequency etc.

Test shows that different estimated parameters are can be preferred under different situations.For example, increase detectability when using near the Beat Signal of variance can a harmonics in checking a plurality of harmonics, and use the absolute value and or derivative average and may be better of derivative during near the Beat Signal checking fundamental frequency.When other detection method failure, can take pattern recognition.Thus, beat detection module 53 can be configured to, and uses one or any combination in these evaluate parameters.

Figure 13 wherein can utilize beat detection module 53 to detect the frequency of cardiac pulses and the example of amplitude range.The frequency range of dotted line indication normal heart, and dark-coloured horizontal frequency band indication can detect the frequency of cardiac pulses in the system of the pumping frequency of utilizing 1.13Hz.The horizontal frequency band of the five elements is represented the different relative value between blood pump and the cardiac pulses, walks to top line the end of from, and scope was from 20: 1,40: 1,60: 1,80: 1 to 100: 1.Compare with the corresponding plot among Fig. 7, the blind area is very little, and showing surpasses direct detecting method when there is cardiac pulses in this beat detection method near it relates to the frequency component (especially its fundamental frequency and corresponding harmonics) that detects blood pump.

At last, Figure 14 is the figure of the performance of monitoring arrangement among illustration Fig. 5.Direct detection and beat with combination detect.Bright frequency band is represented wherein to realize the frequency field that heart detects by direct detecting method, and dark-coloured frequency band is represented wherein to detect the frequency field of realizing that heart detects by beat.The technology of combination makes it can optimize direct detecting method and beat detection method (Fig. 4) individually, to detect in the corresponding frequencies zone.

Above, the present invention mainly is described with reference to several embodiments.Yet, one of ordinary skill in the art will readily recognize that only limit by appended patent claims and restriction, in the scope and spirit of the present invention, other embodiment except top disclosed embodiment equally all is fine.

For example, pressure signal can be derived from any pressure transducer that can expect type, these pick offs are for example operated according to resistive, capacitive character, inductive, magnetic or optics sensing, and utilize one or more each and every one diaphragms, corrugated tube, Bourdon pipe, piezoelectric element, semiconductor subassembly, deformeter, resonance line etc.

And that illustrated embodiment can be used for monitoring is all types of, wherein blood is taken out from patient's blood circulation so that used an extracorporeal blood circuit of handling to it before it is back to this blood circulation.This blood circuit comprises: hemodialysis, blood filtration, plasmapheresis, come off (apheresis), external barrier film oxygenate (extracorporeal membrane oxygenation), assist type blood circulation, and external liver support/dialysis.

And, this monitoring technology can be used for blood pump any kind, produce pressure pulse in blood circuit, not only can be used for aforesaid rotary peristaltic pump, and can be used for the positive-displacement pump of other type, as linear peristaltic pump, membrane pump, and centrifugal pump.

The monitoring technology that it will be readily appreciated by those skilled in the art that invention can detect based on beat separately.Optionally, beat detects and can make up with another detection technique, detects as the stress level according to the described threshold value of foreword as above-mentioned direct detecting method or utilization.This combine detection technology can serial, by any order or executed in parallel.

Those skilled in the art can find the alternate manner of the Beat Signal in the detected pressures signal.Near the selectivity bandpass filtering of different frequency component that comprises above-mentioned blood pump, so that the beat detection, but can save it.This Beat Signal does not need by detecting at the time-domain analysis signal segment.For example, if this signal segment is longer at the cycle of this Beat Signal, then can be in the frequency domain detection beat, for example after the Fourier transform of aforementioned envelope.

And the notion of invention is not limited to Digital Signal Processing.Figure 15 illustration be used for the example combinations of analog of the beat component of detected pressures signal.Isolated system itself is known, and the technical staff can obtain the alternative realization easily.The example combinations of analog comprises band filter 151, and band filter 151 is suitable for to importing pressure signal filtering into, to isolate the fundamental frequency (f of pumping installations ₀) component of signal located.Doubler 152 pressure signal and may command the corresponding output signal that is configured to accept filter with the selected multiple that produces fundamental frequency (0.5,1,2.5,3 etc.).Output signal from doubler 152 inputs to controlled band filter 153 as control signal, and controlled band filter 153 is suitable for receiving and imports pressure signal and filtering into.This wave filter 153 is controlled so as to thus, by removing except from other all frequencies near the frequency band the frequency of the control signal of doubler 152, handles this pressure signal (with reference to the step 406 among Fig. 1).Treated pressure signal is inputed to peak detector 154, produce envelope signal thus, subsequently it is fed to high pass filter 155, this high pass filter 155 is removed any DC component from this envelope signal.Optionally, can comprise the low pass filter (not shown), to remove high-frequency noise from this envelope signal.At last, this envelope signal is detected by amplitude detector 156, and amplitude detector 156 is suitable for determining exist/not exist Beat Signal.This amplitude detector can comprise full wave rectifier 156a, low pass filter 156b and the comparator 156c that is fed reference signal in order.If the amplitude at the input signal of comparator 156c exceeds this reference signal, then comparator 156c can export expression and has the signal of Beat Signal, otherwise does not export; Perhaps opposite.

The foregoing invention notion can also be applied to monitor the integrity that is used to transmit other the fluidic flow circuits except blood.Similarly, these flow circuits do not need to be in during patient's fluid is communicated with, and can be connected to the container of any other type.

Figure 16 (a) illustration such flow circuits 20, it is configured to return first container 161 from first container 161 by second container 162 and transmits fluids.Second container 162 can be configured to, and handles fluid (as the dialyser among Fig. 1 6).Alternatively, second container 162 can be handled (cleaning, purification, sterilization etc.) by circulation of fluid.Pumping installations 3 is circulation of fluid in loop 20.Pressure transducer 4d or 4e are configured to indicate the fluid pressure in first container 161 or the flow circuits 20.Pulse generator 163 is associated with first container 161, to produce pressure wave in the fluid therein.For first container 161, pulse generator 163 can be inherent (being similar to patient's heart), for example, adopts the form of pump, vibrator etc.Alternatively, pulse generator 163 can be the independent isolated plant that is engaged to first container, as vibrator, ultrasonic generator etc.Interference between the pressure wave that pressure wave that pulse generator 163 is produced and pumping installations 3 are produced will or be connected in the detected pressure signal of pressure transducer 4d of first container 161 at the pressure transducer 4d that is connected to flow circuits 20 and form beat.As previously mentioned, can be at least in part based on there being or not existing beat in this pressure signal, the monitoring device (not shown) of the integrity by being used for determining flow circuits 20 is analyzed this pressure signal.In this embodiment, and be that this monitoring device can work to the pressure signal from more than one pressure transducer in these disclosed all other embodiments.

Figure 16 (b) illustration such flow circuits 20, it is configured to transmit fluid along the unidirectional route from first container, 161 to second containers 162.As in Figure 16 (a), pulse generator 163 can be associated with first container 161, and can determine the integrity of flow circuits by the monitoring device (not shown) at least in part based on existing in the pressure signal or not having beat.This pressure signal can obtain by the pressure transducer 4d-4f that is connected to first container 161, flow circuits 20 or second container 162.In alternative embodiment, pulse generator 163 can be associated with second container, shown in dotted line among Figure 16 (b).

The structure of Figure 16 (a) and 16 (b) can be with being sent to second container 162 or using by its any kind fluid (being typically liquid).

In a this example, the structure illustration of Figure 16 (a) wherein with blood from container/machine 161 suction by blood processor 162 and be back to the flow circuits of container/machine 161.Although not shown among Figure 16 (a), can instead blood be guided to another container/machine in blood processor 162 downstreams.Blood processor 162 can be to be configured to improve and/or any known devices of analyzing blood.

In another example, second container 162 is dialysers of handling again by pump up water, alternatively with the appropriate chemical medicine, passes through dialyser 162 from first container 161.This flow circuits can closed circuit (in Figure 16 (a)), perhaps open circuit (in Figure 16 (b)).The example of closed circuit dialyser secondary treatment system is known from US2005/0051472.

In another example, the structure delineation of Figure 16 (a) part of dialysate regeneration system, wherein, dialysis solution cycles through dialysate regeneration device 162 and is back to supply department 161 from dialysis solution supply department 161.The example of dialysate regeneration device is known from WO 05/062973.

In another example, Figure 16 (a) and 16 (b) illustration be used for the structure of starting extracorporeal blood circuit via flow circuits 20 to dialyser 162 suction starting (priming) fluids by from supply department 161.

In another example, Figure 16 (a) and 16 (b) illustration be used for by via flow circuits 20 to dialyser/dialyser pipeline 162 suction cleaning fluids, come the flow arrangement of route of the dialysis solution of cleaning and disinfection dialysis machine.This cleaning fluid for example can be hot water, chemical solution etc.

In another example, Figure 16 (a) and 16 (b) illustration be used for the structure of purifying waste water by purifier 162 by from supply department's 161 pump up water.This purifier 162 can use any known water purification techniques, and for example, reverse osmosis, deionization or carbon absorb.

In another example, Figure 16 (a) and 16 (b) illustration be used for providing the structure of purifying waste water to dialysis machine 162, for example, pre-preparation dialysis solution aspect is used therein.

In all these another examples,, it is essential the integrity of monitoring flow circuits 20 with in other application relevant with human or animal patient's medical treatment.This monitoring can realize according to inventive concept disclosed herein.

Claims (30)

1. the method for the integrity of the flow circuits (20) that is communicated with container (161,162) fluid of a monitoring, described flow circuits (20) comprises the pumping installations (3) that is used for by described flow circuits (20) transmitting fluid, said method comprising the steps of:

Reception is from the pressure signal of pressure transducer (4), and described pressure signal is represented the fluid pressure in described container (161,162) or the described flow circuits (20);

Handle described pressure signal, with detect by and the pressure wave that produced of the pulse generator (163) that is associated of described container (161,162) and the pressure wave that produced by described pumping installations (3) between the formed Beat Signal of interference; And

At least in part based on the existence of described Beat Signal or there is not to determine the integrity of described flow circuits (20).

2. method according to claim 1, wherein, by detecting described Beat Signal at the described pressure signal of time-domain analysis.

3. method according to claim 1 and 2, this method also comprises the step of obtaining one or more characteristic frequency relevant with the pumping frequency of described pumping installations (3), and wherein, the treating step comprises and generate at least one filtering pressure signal, in this filtering pressure signal, removed all other characteristic frequency except that a characteristic frequency in described one or more characteristic frequency.

4. method according to claim 3, wherein, described at least one characteristic frequency comprises one or more in half of described pumping frequency, described pumping frequency and the harmonics thereof.

5. according to claim 3 or 4 described methods, wherein, the treating step comprises the step of the envelope of determining described filtering pressure signal.

6. method according to claim 5, wherein, the step of described definite envelope comprises the step of from described filtering pressure signal extraction time order peak value array.

7. according to claim 5 or 6 described methods, wherein, described treatment step also comprise based on described envelope calculate a plurality of derivatives and and variance at least one.

8. according to each the described method in the claim 3 to 7, this method comprises that also at least a portion of comparing described filtering pressure signal and one or more predetermined signal patterns are to detect the step of described Beat Signal.

9. according to each the described method in the claim 3 to 8, wherein, at least one step during described obtaining step may further comprise the steps: at the described pressure signal of frequency-domain analysis to discern described one or more characteristic frequency; Derive the frequency measurement signal from described pumping installations (3); And value of setting that derives the controller (23) of the pumping frequency be suitable for controlling described pumping installations (3).

10. according to the described method of arbitrary aforementioned claim, this method also comprises handles the step of described pressure signal with the component of signal that detects described pulse generator (163) and produced, wherein, the step of the described integrity of determining described flow circuits is also based on the existence of described component of signal or do not exist.

11. method according to claim 10, wherein, the described pressure signal of described processing is condition with the step that detects Beat Signal there not to be described component of signal in described pressure signal.

12. according to the described method of arbitrary aforementioned claim, this method is further comprising the steps of: under the situation that does not have Beat Signal, make the pumping frequency of described pumping installations (3) that predetermined the change be taken place.

13. according to the described method of arbitrary aforementioned claim, this method is further comprising the steps of: make the temporary transient inertia of described pumping installations (3); Discern the frequency of described pulse generator (163); And make described pumping installations (3) quilt so that all such with respect to the frequency shift (FS) of described pulse generator (163) the pumping frequency of all associated frequencies components activates.

14. according to the described method of arbitrary aforementioned claim, wherein, the each several part overlap signal section sequence of described pressure signal is carried out described treatment step, the length of each section is specified by scheduled time window.

15. a method that is used to monitor the integrity in the extracorporeal blood flow loop (20) that is connected to patient's blood vessel, described extracorporeal blood flow loop (20) comprises blood pumping device (3), said method comprising the steps of:

Reception is from the pressure signal of the pressure transducer (4) in the described blood flow loop (20);

Handle described pressure signal, the pressure wave that produces with the heart that detects by described patient with by the formed Beat Signal of interference between the pressure wave of described blood pumping device (3) generation; And

At least in part based on the existence of described Beat Signal or there is not to determine the integrity in described blood flow loop (20).

16. an equipment that is used for the integrity of the flow circuits (20) that is communicated with container (161,162) fluid of monitoring, described flow circuits (20) comprises the pumping installations (3) that is used for by described flow circuits (20) transmitting fluid, and described equipment comprises:

At the input part from the pressure signal of pressure transducer (4), described pressure signal is represented the fluid pressure in described container (161,162) or the described flow circuits (20); With

Signal processor (29), this signal processor (29) comprises first module (53), this first module (53) is configured to handle described pressure signal, with detect by and the pressure wave that produced of the pulse generator (163) that is associated of described container (161,162) and the pressure wave that produced by described pumping installations (3) between the formed Beat Signal of interference, described signal processor (29) is configured at least in part based on the existence of described Beat Signal or does not have to determine the integrity of described flow circuits (20).

17. equipment according to claim 16, wherein, described first module (53) is configured to, by detecting described Beat Signal at the described pressure signal of time-domain analysis.

18. according to claim 16 or 17 described equipment, wherein, described first module (53) also is configured to obtain one or more characteristic frequency relevant with the pumping frequency of described pumping installations (3), and be configured to generate at least one filtering pressure signal, in this filtering pressure signal, removed all other characteristic frequency except that a characteristic frequency in described one or more characteristic frequency.

19. equipment according to claim 18, wherein, described first module (53) also is configured to, and determines the envelope of described filtering pressure signal.

20. equipment according to claim 19, wherein, described first module (53) also is configured to, and determines described envelope by extraction time from described filtering pressure signal order peak value array.

21. according to claim 19 or 20 described equipment, wherein, described first module (53) also is configured to, based on described envelope calculate a plurality of derivatives and and variance at least one.

22. according to each the described equipment in the claim 18 to 21, wherein, described first module (53) also is configured to, and compares at least a portion of described filtering pressure signal and one or more predetermined signal patterns to detect described Beat Signal.

23. according to each the described equipment in the claim 16 to 22, wherein, described signal processor (29) comprises second module (52), this second module (52) is configured to handle described pressure signal to detect the component of signal that described pulse generator (163) is produced, wherein, described signal processor (29) is configured to also based on the existence of described component of signal or does not have to determine the integrity of described flow circuits.

24. equipment according to claim 23, wherein, described signal processor (29) is configured to, operate described first module (53) and described second module (52) in order, so that described first module (53) is only operated when described second module (52) does not detect described component of signal in described pressure signal.

25. according to each the described equipment in the claim 16 to 24, wherein, described signal processor (29) is configured to, and under the situation that does not have Beat Signal, makes the pumping frequency of described pumping installations (3) that predetermined the change be taken place.

26. according to each the described equipment in the claim 16 to 25, wherein, described signal processor (29) is configured to, make the temporary transient inertia of described pumping installations (3), discern the frequency of described pulse generator (163), and make described pumping installations (3) so that all such with respect to the frequency shift (FS) of described pulse generator (163) the pumping frequency of all associated frequencies components is activated.

27. an equipment that is used for the integrity of the flow circuits (20) that is communicated with container (161,162) fluid of monitoring, described flow circuits (20) comprises the pumping installations (3) that is used for by described flow circuits (20) transmitting fluid, and described equipment comprises:

Be used for receiving the device (28) from the pressure signal of pressure transducer (4), described pressure signal is represented the fluid pressure in described container (161,162) or the described flow circuits (20);

Be used to handle described pressure signal, with detect by and the pressure wave that produced of the pulse generator (163) that is associated of described container (161,162) and the pressure wave that produced by described pumping installations (3) between the device (53) of the formed Beat Signal of interference; And

Be used at least in part based on the existence of described Beat Signal or do not have to determine the device (53) of the integrity of described flow circuits (20).

28. an equipment that is used to monitor the integrity in the extracorporeal blood flow loop (20) that is connected to patient's blood vessel, described extracorporeal blood flow loop (20) comprises blood pumping device (3), and described equipment comprises:

Be used for the device (28) of reception from the pressure signal of the pressure transducer (4) in described blood flow loop (20);

Be used to handle described pressure signal, pressure wave that produces with the heart that detects by described patient and device (53) by the formed Beat Signal of interference between the pressure wave of described blood pumping device (3) generation; And

Be used at least in part based on the existence of described Beat Signal or do not have to determine the device (53) of the integrity in described blood flow loop (20).

29. comprising, a computer program, this computer program be used for making the instruction of computer execution according to each described method of claim 1 to 15.

30. equipment that is used for extracorporeal blood treatment, this equipment comprises extracorporeal blood flow loop (20), this extracorporeal blood flow loop (20) comprises blood pumping device (3), be arranged in the described blood flow loop (20) pressure transducer (4) and according to each the described equipment in the claim 16 to 28.

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